#region License
// Copyright (c) 2007 James Newton-King
//
// Permission is hereby granted, free of charge, to any person
// obtaining a copy of this software and associated documentation
// files (the "Software"), to deal in the Software without
// restriction, including without limitation the rights to use,
// copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following
// conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
// OTHER DEALINGS IN THE SOFTWARE.
#endregion

using System;
using System.Collections.Generic;

namespace Newtonsoft.Utilities.Collections
{
  public class ReverseComparer<T> : IComparer<T> where T : IComparable<T>
  {
    private static ReverseComparer<T> _defaultComparer;
    private readonly IComparer<T> _initialComparer;

    public ReverseComparer(IComparer<T> initialComparer)
    {
      _initialComparer = initialComparer;
    }

    public int Compare(T x, T y)
    {
      return -(_initialComparer.Compare(x, y));
    }

    public static ReverseComparer<T> Default
    {
      get
      {
        ReverseComparer<T> defaultComparer = _defaultComparer;
        if (defaultComparer == null)
        {
          defaultComparer = new ReverseComparer<T>(Comparer<T>.Default);
          _defaultComparer = defaultComparer;
        }
        return defaultComparer;
      }
    }
  }
}